Jia Y, Guo D, Zhang K, et al. - In this two‐sample Mendelian randomization (MR) study, researchers analyzed the causal impact of serum matrix metalloproteinase‐8 (MMP‐8) concentrations on the risk of ischaemic stroke, ischaemic stroke subtypes and coronary artery disease. A genome-wide association study of 6,049 European individuals identified ten independent single-nucleotide polymorphisms related to serum MMP8 concentrations as instrumental variables. The Multiancestry Genome-wide Association Study of Stroke consortium, which included 446,696 Europeans, provided genetic association estimates for ischaemic stroke. MMP-8 levels were not found to have a significant causal relationship with total ischaemic stroke, large artery stroke, or cardioembolic stroke. High serum MMP‐8 concentrations were causally linked to increased risks of small vessel stroke and coronary artery disease. The mechanism underlying serum MMP-8's effect on the vascular system warrants further investigation.